Traffic signal switch



April 14-, 1936 D, P PQTTER 2,037,145

. TRAFFIC SIGNAL SWITCH Filed July 24, 1935 2 Sheets-Sheet l Inveniol TRAFFIC SIGNAL SWITCH Filed July 24, 1955 2 Sheets-Sheet 2 lnvenlor flaw/a5 E P077 Patented Apr. 14, 1936 UNITED STATES PATENT OFFICE TRAFFIC SIGNAL SWITCH David P. Potter, Mason, Mich.

Application July 24, 1933, Serial No. 681,979

1 Claim. (cram-s6) This invention relates to traffic signals of the type used at intersections for controlling traffic.

The invention consists primarily in the provision of an improved switch for controlling traflic signals of the character above mentioned, to-

gether with operating mechanism for the switch.

The invention together with its numerous objects and advantages will be best understood from a study of the following description taken in con- 0: nection with the accompanying drawings wherein is illustrated a preferred embodiment of the invention.

It is to be understood at the outset that the invention is in no wise intended to be restricted to 15. the precise details of construction, combination and arrangement of elements as herein illustrated and described, other than may be necessary to meet the requirements of the prior art and scope of the appended claim.

In the drawings:

Figure 1 is a sectional view through a treadle, a switch box, and mechanism for controlling operation of the switch from the treadle this figure showing the parts in position when the treadle is in raised position.

Figure 1a is a view similar to Figure 1 but showing the parts with the treadle in depressed position.

Figure 2 is a perspective View of a rack bar and an operating hook associated therewith.

Figure 3 is a perspective view of a connecting link and a weight associated therewith.

Figure 4 is a sectional view taken substantially on the line 4-4 of Figure 1.

In accordance with the present invention, there is provided in each lane of trafiic, at the right side of the lane a suitable distance inwardly from the intersection of the streets a treadle 2| that is of a length substantially equal to one-half the width of the street or traffic lane so as to normally accommodate the two front or rear wheels of an automobile in a manner to cause the treadle 2| to move downwardly in a substantially vertical plane. The treadle 2| is normally supported slightly above ground level through the medium of coil springs 22 disposed adjacent the ends of the treadle.

Adjacent to the curbing there is mounted a suitable tubular standard 23 in which are mounted for reciprocation sections 24, 25' of a two-part plunger. Section 24 at its lower end is pivotally connected with a rod 25 which adjacent one end is pivotally mounted as at 26 beneath the treadle 55 2|. At said pivoted end the rod 25 is pivotally connected with a depending bracket 21 provided on the under side of the treadle 2|.

Arranged within the tubular standard 23 be tween the confronting ends of the sections 24, 24' is a coil spring 28 that operates to separate the sections 24, 24, urging the section 24 downwardly and the section 24 upwardly, the sections 24 being moved upwardly when the spring 28 is compressed by the upward movement of the section 24.

On the upper end of the standard 23 there is 1 mounted a switch casing 29.

Mounted in the casing 29 is an electric switch which is in suitable circuit with the lamps of the trafiic signal (not shown) and said switch includes a fixed contact 30 and a movable contact 15 3| that is mounted on one end of a rocker arm 32. Arm 32 is pivotally mounted intermediate its ends on a depending bracket 33 extending downwardly from the top wall of the casing 29.

For opening and closing the aforementioned 20 switch there is provided in the casing 29 a rack bar 34 that is slidable vertically through a suitable guide 35, and at its lower end bar 34 is pivotally connected with the plunger section 24' through the medium of a link 36. Link 36 at the end thereof pivotally connected with the section 24' is provided with an arm 31 from which is suspended a weight 38 that acts on the link 36, when the arm 31 is raised above the bottom of the casing 29, for holding the link 36 in a substan- 30 tially vertical position. However when the arm 31 engages the bottom of the casing it will move the link 36 to the left in Figure 1 and thus tilt the rack bar in the position shown in Figure 1. Suitably secured to the upper end of the rack bar 34 35 is a hook 39 that engages the free end of the rocker arm 32 in a manner to normally retain the contact 3| out of engagement with the contact 39. See Figure 1.

Governor means is provided for controlling 40 the speed of downward movement of the rack bar 34, and such means consists of a shaft 40 journalled in the casing 29 and provided with a pinion 4| that is in mesh with the teeth of the rack bar 34. The shaft 40 is connected through the medium of beveled gearing 42 with a second shaft 43 also suitably journalled in the casing 29 and having a gearing connection 44 with a governor shaft 45 suitably journalled within the casing. Mounted on the shaft 45 is a centrifugal 50 governor designated generally by the reference character 46. On the shiftable end of the governor 46 there is provided a disk 41 that is engageable with one end of a stop lever 48 that is rockably mounted on a bracket 49. For limiting the rocking movement of the lever 48 and thus controlling the expanding action of the governor 46 there is mounted on the top of the casing 29 an adjustable stop device which is in the nature of a lug 50 having threadedly engaged therewith a screw 5|, one end of which is arranged in the path of the upper end of the lever 48, said lever 48 at its upper end operating in a suitable slot provided in the top wall of the casing 29 as will be clear from a study of Figure 1.-

The operation of the invention is thought apparent from the foregoing. As a vehicle approaches the intersection, the vehicle passes over the treadle 2| thus depressing the latter and rocking the rod 25. Rocking movement of the rod 25 forces the rod section 24 upwardly and the movement of the section 24 is transmitted to the section 24 through the spring 28. The upward movement of the section 24' causes the rack bar 34 to move upwardly to disengage hook 39 from the arm 32. Arm 32 by gravity assisted by a weight 32a on the contact-equipped end thereof swings in an anti-clockwise direction to engage contact 3| with contact 30 for closing the circuit through the red lamps arranged on opposite sides of the trafiic signal (not shown) and. facing the traihc lanes that extend at right angles to the traffic lane in which the vehicle approaching the intersection is travelling, and also close the circuits through the green lamps on the sides of the traflic signal (not shown) facing the lane in which the vehicle is travelling.

As the said vehicle passes from the treadle 2| and crosses the intersection the treadle 2| under action of springs 22 will move upwardly and the rod 24 will move downwardly under action of spring 28 and by gravity. The rod 24' will also move downwardly under the action of gravity and the downward movement of the rack bar 34 Will also result. However as the weight 38 acting on the arm 31 and the link 36 and moves the rack bar against the pinion 4|, the speed at which the rod 34 moves downwardly will be controlled by the governor mechanism, and the timing will be such as to insure the illumination of the proper signal lamps for a period of time necessary for the vehicle to clear the intersection.

Thus it will be seen that when the treadle is in raised position the sections 24 and 24 and spring 28 will be in lowered position, with the arm 31 engaging a part of the bottom of the casing 29, so that the rack bar is in tilted position and out of engagement with the pinion 4|. Then when the treadle is depressed by a vehicle passing over it the parts will be raised so that i the rack bar will disengage the switch 32 so that the switch can close and the rack bar will disengage the switch before the weight 38 connected with the arm 31 can swing the rack bar into engagement with the pinion. Thus the governor acts to retard downward movement of the rack bar so that the switch will not be opened until the vehicle has had time to pass the intersection.

Having thus described my invention, what I claim as new is:

In a vehicle operated switch controlling device, a casing, a tubular standard depending from the casing, upper and lower weight sections slidably arranged in the tubular member, a coil spring between the sections raising the upper section when the lower section is raised by a vehicle, a bell crank pivoted to the upper end of the upper section, a rack bar having its lower end pivoted to one end of the bell crank, a weight connected to the other end of the bell crank, the last mentioned end portion of the bell crank engaging the bottom of the casing when the weight sections are in lowered position, a guide in the casing for the rack bar of greater length than the width of the rack bar, a switch engaging part on the upper end of the rack bar, a. pinion rotatably mounted in the casing and engaged by the rack bar when the same is acted on by the weight of the bell crank and governor means driven from the pinion when the same is actuated by the descending rack bar said governor means retarding downward movement of the rack bar.

DAVID P. PO'I'IER. 

